Equal Groups
Addition and Subtraction
Subtraction Strategies
One or Two-Step Problems
Money and Time
100
Is 12 an even number? How do you know?
Yes. 12 is an even number because 6 + 6 = 12.
100
Which equation does this number line show?
57 + 38 = 95
100
Which does the number line show?
A. 90 - 10 = 30
B. Count back by 10 six times from 90
C. 30 + 50 = 90
D. 90 + 60 = 150
B. Count back by 10 six times from 90
100
Someone finds $90 on the ground. They quickly spend $50. How much money do they have?
They have $40.
100
200
Which doubles fact shows 16 is an even number?
A. 10 + 6 = 16
B. 12 + 4 = 16
C. 5 + 11 = 16
D. 8 + 8 = 16
D. 8 + 8 = 16
200
Which addition equation helps you solve 98 - 34?
A. 98 + 34 = __
B. 98 - __ = 34
C. 34 + __ = 98
D. 34 + 98 = __
C. 34 + __ = 98
200
Which equation requires regrouping to solve?
A. 52 - 11 = __
B. 38 - 30 = __
C. 42 - 16 = __
D. 95 - 2 = __
C. 42 - 16 = __
200
Ms. Thiele has 20 fewer books than Mr. Llanes. Mr. Llanes has 45 books. How many books does Ms. Thiele have? Give an equation that matches.
Ms. Thiele has 25 books.
45 - 20 = 25
200
What is the total value of these coins?
43¢
300
Mr. Llanes has 15 boxes of colored pencils in his classroom. Which equation shows a way Mr. Llanes could make an array?
A. 10 + 5 = 15
B. 5 + 5 + 5 = 15
C. 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 15
D. 3 + 3 + 3 + 3 = 15
B. 5 + 5 + 5 = 15
300
Which equation requires regrouping to solve?
A. 13 + 16 = __
B. 80 + 15 = __
C. 25 + 21 = __
D. 38 + 29 = __
D. 38 + 29 = __
300
Ms. Freyvert wants to make this problem easier to solve by breaking apart 16 before subtracting.
Did she do it correctly? Explain.
No. To break apart the 6 in 16, you need 2 and 4.
300
Ms. Hueston has 28 stuffed animals and 13 books. She gives 10 teddy bears to the other second grade teachers. How many stuffed animals does Ms. Hueston have left?
Ms. Hueston has 18 stuffed animals left.
28 - 10 = 18
300
You found 3 dimes and a quarter on the ground outside. Is that enough money to buy a sticker for 50¢? Will you have any change left?
Yes, it is enough to buy a sticker.
25, 35, 45, 55 cents
You will have 5 cents left.
400
Which sum is an even number?
A. 7 + 2 = 9
B. 2 + 4 = 6
C. 2 + 3 = 5
D. 10 + 1 = 11
B. 2 + 4 = 6
400
Is this equation equal to 78?
23 + 12 + 43 = ?
Yes, 23 + 12 + 43 = 78.
Add the tens: 20 + 10 + 40 = 70
Add the ones: 3 + 2 + 3 = 8
Add the partial sums: 70 + 8 = 78
400
True or False
To solve 56 - 43, you can subtract 4 from 56 and then subtract 3.
False
To solve 56 - 43, you can subtract 40 from 56 and then subtract 3.
400
Mr. Llanes needs 50 balloons for a project.
He finds 20 in his classroom.
Ms. Thiele gives him 10 balloons.
How many more balloons does Mr. Llanes need for his project? What equations did you need to solve?
Mr. Llanes needs 20 more balloons.
20 + 10 = 30
50 - 30 = 20
400
What time does the clock show?
A. 10:45
B. quarter past 9
C. quarter to 10
D. 45 minutes after 6
E. 9 o'clock
C. quarter to 10
500
Ms. Thiele has 12 plants in her garden.
Choose all of the equations Ms. Thiele could use to make an array in her garden.
A. 10 + 2 = 12
B. 6 + 6 = 12
C. 3 + 3 + 3 + 3 = 12
D. 7 + 5 = 12
E. 1 + 11 = 12
B. 6 + 6 = 12
and
C. 3 + 3 + 3 + 3 = 12
500
What number completes the equations?
75 - 25 = __
25 + __ = 75
50
500
The second grade teachers need to prove that compensation is not so tricky.
They want to subtract 75 - 18. To make 18 easier to subtract from 75, they make the new equation, 77 - 20.
75 - 18 = __
↓? ↓?
77 - 20 = __
What did the teachers add to each number in order to show the compensation strategy? What number completes both equations?
The teachers added 2 to each number.
75 - 18 = 57
↓+2 ↓+2
77 - 20 = 57
500
Ms. Hamor has 30 more mini clocks in her room than Ms. Freyvert.
Ms. Hamor has 50 mini clocks.
Ms. Freyvert wants to know how many mini clocks she has. Which equation does NOT help Ms. Freyvert find out how many clocks she has?
A. 30 + 50 = __
B. 30 + __ = 50
C. 50 - 30 = __
D. __ + 30 = 50
A. 30 + 50 = __
500
An analog clock shows the hour hand between 2 and the 3. The minute hand is on the 3. What time does the clock show? Does the clock show half past 2?
No. The clock shows 2:15 which can be read as...
*extra 100 points to teams who can correctly tell other ways to tell someone the time is 2:15*